'Is he okay?' Molly asked as soon as John walked through the door of the lab. 'Only they said he was doing okay when I phoned last night. Has something happened?'

'No, he's fine - well, you know, not fine, but he's getting there slowly,' John said, watching the relief flood her face. 'That's not why I'm here. I need to talk to you about the drugs, Molly. The ones that Sherlock may or may not have been using.'

Molly misinterpreted the tension in John's face and instantly looked guilty. 'I'm sorry, John,' she said, cheeks flaming, words tripping over each other in her urge to confess. 'I didn't want to be part of it, but you know Sherlock - he said it was important.'

'Part of what?' John asked, 'Molly what are you talking about?'

'Me faking his urine toxicology results of course. Only he was so insistent, I couldn't -''

John groaned and slapped himself on the forehead. 'Of course, how could I have been so stupid. That slap, it was staged, wasn't it? Was that his idea?'

'The first one was, the others were - dramatic license.' Molly suppressed a grin as she looked down. 'Thing is, it was rather satisfying, and he couldn't exactly complain, could he?'

'So the slap was faked and the drug test?'

'Faked too,' Molly said with a quick nod. 'I swapped urine samples.'

'Billy's?' John asked, but he already knew the answer. Damn, he had been so careful; he had followed Sherlock into the Gents to ensure that there was no sleight of hand or filling the sample pot up with Lucozade involved. He'd seen enough attempts at faking drug tests during his time as an army RMO to know all the tricks there were, but the one thing that had never occurred to him was that Molly might be involved too.

'But his pupils Molly - his pupils were-'

'Constricted, yes, I know. Pilocarpine eye drops. I got them from a friend who works in the Eye Clinic. They must have made his vision a bit blurred, but as he said, it wasn't as if he had to drive or anything.'

John's brain was turning somersaults. So the drug test was faked, the characteristic constricted pupils of heroin use had been faked too. Exactly how deep was this rabbit hole going to go?

'But why, Molly. Why was it so important that I thought he was using?'

'No idea. He wouldn't tell me. But it was faked, John. It was all faked. He's okay. He's clean.'

'No, he's not,' John said, pulling the copy of The Pickwick Papers out of his bag, and triggering the lock. 'Look what I found in 221b.'

Molly frowned, and reached for a pair of gloves before picking up one of the bags and looking at it closely. 'Could be just about anything,' she said. 'I can run it through the analyser if you like - see what it turns up?'

'Please,' said John. 'All three if you can.'

'What happened to this one?' Molly asked, picking up the first bag that John had opened.

'It's sherbert,' John said. 'Well at least, it tasted like sherbert. But let's analyse it anyway.'

'Bet you a fiver that there isn't a trace of illegal substance in any of them,' Molly said smugly, as she walked over to the analyser and started to prepare the samples. 'It's all part of the plan, John. He wanted to make everyone think that he was using.'

'His toxicology from The London came back as positive, Molly,' John said, exasperated, as his mind turned somersaults trying to work out what the hell was going on.

Molly froze, pipette suspended in mid-air. 'Positive for what?' She asked, without turning round.

'Heroin, cocaine and ketamine,' John told her.

Molly fed the first sample into the analyser silently before turning round and facing John.

'He could have had a friend in the lab. It could still have been faked,' she said, and John could see her mind was going through the same processes that his was. Denial, anger, acceptance. Although she didn't seem to have got as far as acceptance yet.

'You think he planned to get shot and end up in A&E at The London?' John asked. 'No, Molly, it's real. It was a double bluff. For some reason, he didn't want you to know the truth. He's been using all right. His opiate tolerance is sky-high apart from anything else. You can't face that, tolerance only comes from one thing - from using. He's needed huge doses of opiates to keep him comfortable, because his body is so used to them. There is no other explanation.'

'No!' Molly said looking horrified.

'Have you got an adequate explanation for what I've just told you?'

'No,' she said shaking her head. 'But I trust Sherlock, and I trust this analyser,' she said patting it, and it tells me - ' she pressed the print button and triumphantly handed the piece of paper spewed off from the side of the machine to John. 'It tells me that that white powder was baking powder and a harmless local anaesthetic powder - a form of lignocaine.'

'The one I thought was sherbert?'

'No, the one in the unopened bag,' she said with a grin. 'It's fake, John. It's fake cocaine, designed to look like cocaine to the casual observer, or taster, but there's nothing illegal about it.'

The results from the other two bags were similarly innocuous. One contained sucrose, citric acid, tartaric acid, and sodium bicarbonate - sherbert in fact, as John had suspected. The other sample, the one that had made John's tongue go numb, contained exactly the same innocuous substances as the first sample.

'Told you,' Molly said smugly. 'I think you owe me a fiver.'

John shook his head, 'I don't understand,' he said. 'Why would he do that? There isn't anywhere else that he could be keeping his stash. I looked everywhere.'

'Because they're not there, John. That has to be an explanation, surely?'

'He has been using though, Molly. His drug test proved that.'

'If I was you, I'd get another sample, John. Take it yourself, bring it to me and I'll analyse it.'

'But we know he's on opiates now, and the cocaine will be long gone, ketamine too.'

'Hair test,' Molly said promptly. 'That will tell us what he's been using and for how long.'

'What is he up to Molly, has he told you?'

She shook her head, 'I only know what he told you. It's all about Magnussen. He wanted Magnussen to think that he was using. Why, I couldn't say.'

'But he came here to ask you to help?'

Molly hesitated for only a second. 'He comes here all the time, John. Brings samples to put through the analyser, uses the lab kit. Sometimes he even brings coffee.'

'Sherlock brings you coffee?'

She shrugged. 'Sometimes,' she said. 'I think he's been lonely, John. He misses you. He wouldn't thank me for saying it, but - well. There it is.'

'I feel guilty enough, Molly, without you adding to it.'

'I know, and I'm sorry. I'm just - I'm worried for him, you know? I've never seen him so driven on a case, not since Moriarty. You used to provide the brakes, stop him from doing anything too stupid, but without you about, he's lost that. I don't think that there's any limit to what he'll do this time, and we both know how far he's prepared to go when he's like that.'

John thought about Moriarty, and the roof, and the fall, and the body on the pavement and the two years of not knowing,

'What do I do, Molly?' he asked.

'Talk to him,' Molly said. 'You know Sherlock, he likes to talk. Of course you might not be able to get him to talk about what you want him to, but still. He needs to know that you care, John.'

'Saving his life wasn't enough?' John asked jokingly.

'Well we've all done that,' she said lightly. 'That's what we all do isn't it? But if he is using drugs John, if he is using again, then he's going to need all the support that he can get.'

There is a new chapter of Conversations and Conspiracies up, which fits between this chapter and the next, so please do have a look.

To the Guest reviewer who suggested that it should be Fratres not Fratros - turns out neither is right! Fratres is more correct, as it's the Greek form of the word, but the correct word is Philia. Fortunately for me, John got it wrong too. All will be revealed...